Structural heart Disease Flashcards
What are the six main congenital structural heart diseases?
Atrial septal defect
Ventricular septal defect
Coarction of aorta
Patent Foramen ovale
Patent ductus arteriousus
Tetralogy of Fallot (TOF)
What is atrial septal defect?
A hole in the septum that divides the atria
What is ventricular septal defect?
A hole in the septum between the ventricles
What is tetralogy of fallot?
A combination of: ventricular septal defect, pulmonary stenosis, aortic valve sitting directly of top of ventricular septal defect and ventricular hypertrophy
What is coarctation of aorta?
A part of the aorta is narrower than usual which can block normal blood flow and back up flow into the left ventricle of the heart
What are the four types of valvular defects?
Aortic stenosis, aortic regurgitation, mitral stenosis and mitral regurgitation
What is the most common valvular disease in the US and Europe?
Aortic stenosis
What disease precedes aortic stenosis?
Aortic sclerosis (aortic valve thickening without flow limitation)
How is aortic stenosis often detected?
Presence of an early-peaking, systolic ejection murmur and confirmed by echocardiography
What risk factors are associated with aortic stenosis?
Hypertension, LDL levels, elevated Crp, congenital bicuspid valves, chronic kidney disease, radiotherapy, older age
what are the causes of aortic stenosis? (3)
Rheumatic heart disease, congenital heart disease, calcium build up
What is the pathophysiology behind aortic stenosis?
Long standing pressure overload leading to left ventricular hypertrophy
Increased after load as ventricle maintains a normal wall stress despite the pressure overload produced by stenosis.
Stenosis worsen so adaptive mechanism fells and left ventricular wall stress increases..
Causes systolic function decline
How is the severity of aortic stenosis determined?
By calculating speed of blood flow through the valve.
Severe if >4m/s. Done by trans-thoracic-echocardiogram
What is the aortic regurgitation?
Diastolic leakage of blood from the aorta into the left ventricle due to incompetence of valve resulting in intrinsic valve disease or dilation of aortic root
Which is the least common out of: aortic stenosis, mitral regurgitation and aortic regurgitation
Aortic regurgitation
What what are the congenital and acquired causes of aortic regurgitation?
Rheumatic heart disease, infective endocarditis, aortic valve stenosis, congenital heart defects, congenital bicuspid valves
What are the causes of aortic root dilation that precede aortic regurgitation?
Marfans syndrome
Connective tissue disease/ collagen vascular diseases
Idiopathic
Ankylosing spondilytis
Trauma
Is aortic regurgitation chronic or acute?
Can be both: chronic culminating into congestive cardiac failure.
Acute: medical emergency presenting with sudden onset of pulmonary oedema and hypotension or cardiogenic shock
What is the pathophysiology behind acute aortic regurgitation?
Increased blood volume in LV during systole leading to an increase in end diastolic pressure and pulmonary venous pressure, leading to dyspnoea and pulmonary oedema-> heart failure -> cardiogenic shock
What is the pathophysiology behind chronic aortic regurgitation?
Gradual increase in LV volume, LV enlargement and hypertrophy.
In early stages ejection fraction normal, after some time falls and LV end systolic volume rises
Eventually LV dyspnoea and lower coronary perfusion, ischaemia, necrosis and apoptosis
Outline the presentation of acute aortic regurgitation?
Cardiogenic shock, tachycardia, cyanosis, pulmonary oedema and Austin flint murmur
Outline the presentation of chronic aortic regurgitation
Wide pulse pressure, corridor, pistol shot pulse
What investigations are done in the diagnosis of aortic regurgitation?
Transthoracic echocardiography
Chest x ray
Cardiac catheterisation
Cardiac MRI/CT scan
What are the management options for acute aortic regurgitation?
Ionotropes/ vasodilators and valve replacement/repair
What are the Management options for chronic asymptomatic and chronic symptomatic aortic regurgitation?
Chronic asymptomatic: if LV function is normal can be managed by drugs
Chronic symptomatic: valve replacement with adjunct vasodilator therapy
What preventative measure can be put in place to avoid aortic regurgitation?
Treatment of rheumatic fever and infective endocarditis
What is mitral stenosis
Narrowing of the valve between the left aorta and ventricle
What are the causes of mitral stenosis?
Rheumatic fever, carcinoid syndrome, use of serotonergic drugs, SLE, mitral annular calcification due to aging, whipple disease
Outline the pathophysiology behind mitral stenosis
Exercise/ tachycardia result in exertional dyspnoea due to increased left atrial pressure
Severe mitral stenosis leads to increase in left atrial pressure, transudation of fluid into the lung interstitium leading to dyspnoea at rest or exertion.
Pulmonary hypertension may develop as a result of it
What are the long term effects of mitral stenosis?
Increased pressure in LA.
Increased strain causes dilation of LA
Proarrythmogenic
How is mitral stenosis detected?
Heard during diastole, trickier to recognise
What happens when you have both mitral and aortic stenosis on the left side?
Increased afterload on left ventricle, has to work harder to pump blood, contraction is less effective, abnormal remodelling, left ventricular hypertrophy
What are the causes of mitral regurgitation?
Rheumatic fever, mitral valve prolapse, infective endocarditis, if LV dilates too much -> leaking of valve
What are the immediate effects associated with mitral regurgitation?
Regurgitation of blood when LV contracts, less cardiac output, less blood being pumped out of aorta, less volume of blood reaching body
Why is it essential that mitral regurgitation is treated?
Can lead to death by heart failure, become congested and may need appropriate medication, diuretics. Important to treat and replace valve when severe
How is mitral regurgitation detected?
Systolic murmur
How is progressive asymptomatic mitral stenosis managed?
No therapy required
How is severe asymptomatic mitral stenosis managed?
No therapy generally required adjuvant balloon valvotomy
What are the management options for severe symptomatic mitral stenosis?
Diuretic, balloon valvotomy, valve replacement and repair adjuvant beta blockers
How is acute mitral regurgitation managed?
Emergency surgery adjunct. Preoperative diuretics. adjunct intra-aortic balloon counterpulsation
What are the management options for chronic asymptomatic mitral regurgitation?
ACE inhibitors, beta blockers if left ventricular ejection fraction is less than 60%. Surgery
What are the management options for chronic symptomatic mitral regurgitation?
Surgery plus medical treatment. If left ventricular ejection fraction is less than 30% intra-aortic balloon counterpulsation
What is a cardiomyopathy?
A disease of the heart muscle that makes it harder for heart to pump blood to the rest of the body
What are the three main types of cardiomyopathy?
Dilated, hypertrophic and restrictive
What percentages of the causes of dilated cardiomyopathy are familial?
25%
What are the familial causes of dilated cardiomyopathy?
Primary without family history - idiopathic
what are the secondary causes of dilated cardiomyopathy?
Heart valve disease, after child birth, thyroid disease, myocarditis, alcoholism, autoimmune disorders, ingestion of drugs, mitochondrial disorders
What is dilated cardiomyopathy?
Causes heart chambers to thin and stretch, growing larger
What is hypertrophic cardiomyopathy?
Heart muscle cells enlarge and walls of heart chamber thicken
What is restrictive cardiomyopathy?
Fatty fibrous tissue replaces normal heart muscle
Outline the abnormal physiology of dilated cardiomyopathy
Enlargement of the left ventricle
•lower ejection fraction and increase in the ventricular wall stress and end systolic volumes.
• Early compensatory mechanisms include an increase in heart rate and tone of the peripheral vascular system.
•neurohumoral activation of the renin-angiotensin aldosterone system and an increase in circulating levels of catecholamines.
•levels of natriuretic peptides are also increased.
•Eventually these compensatory mechanisms become overwhelmed and the heart fails.
How does dilated cardiomyopathy usually present?
Dyspnoea, displaced apex beat, S3 or systolic murmur
fatigue,
angina,
pulmonary congestion
low cardiac output
What investigations are conducted to confirm dilated cardiomyopathy?
Genetic Testing
•Viral serology
•ECG
•Chest X ray
•Cardiac catheterisation
•Cardiac MRI/CT Scan
•Exercise stress test
•Echocardiography
What diet modifications are needed to manage dilated cardiomyopathy?
Fluid and Na+ restriction
How do we treat the underlying causes of dilated cardiomyopathy?
Immunosuppressant for sarcoidosis and myocarditis
Phlebotomy for haemochromatosis
How do we manage the symptoms of heart failure associated with dilated cardiomyopathy?
ACEi, beta-blockers with addition of diuretics and angiotensin2 receptor antagonists
In the treatment of the symptoms of heart failure associated with dilated cardiomyopathy, what should be done if following ACEi and beta-blockers, the patient develops a cough, hypotension and/or renal dysfunction?
Lower dose of ACEi
If medical treatment (ACEi and beta-blockers with diuretics and angiotensin2 receptor antagonists) is ineffective in treating the symptoms of heart failure associated with dilated cardiomyopathy, what is the next step in management?
For a surgical candidate: LVAD or orthotopic heart transplantation
For a non-surgical candidate: possible LVAD or optimisation of medical management
What is given to manage the arrhythmias associated with dilated cardiomyopathy?
Amiodarone, defoteilide
What is given to prevent thrombo-embolic events associated with heart failure in someone with a HX of TE, severe systolic dysfunction or ventricular dilatation?
Anticoagulants such as warfarin
What are the characteristics of cardiac hypertrophy?
May have abnormal ECG, left ventricles abnormally thickened
May have abnormal thickening in wall in between chambers
can obstruct blood flow through the aorta
Murmur can mimic aortic stenosis, heard in systole ‘ejection systolic murmur’
A dilated heart has what affect on contractility?
What can cause this?
Poor contractility (law of LaPlace)
Stress induced, peripartum, sarcoidosis, immune diseases, ischaemic etiology
What is needed to be done in investigating a dilated heart to diagnose the cause and manage the patient?
Angiogram
Also family screening
What is arrythmogenic right ventricular cardiomyopathy?
group of disorders which can lead to abnormal ventricular arrythmia -> abnormal contraction, impaired cardiac output
What are the affects of infiltration of fat into the heart?
Abnormal diameter and function, dilated
Not pumping effectively, can also affect LV as intrinsically linked
May not be symptomatic
Can cause ventricular tachycardia -> lead to sudden death (must check for family history of this)
How are heart valve lesions treated?
By replacing the valve before the patient becomes symptomatic or before the heart decompensates
What is the hallmark of hypertrophic cardiomyopathy?
Hypertrophy that is inappropriate, often asymmetrical, and occurs in the absence of an obvious hypertrophy stimulus
In hypertrophic cardiomyopathy, where is the most frequent site of hypertrophy?
Interventricular septum, which results in an obstruction of flow through the left ventricular outflow tract
Outline the abnormal physiology associated with hypertrophic cardiomyopathy
Most patients with HCM have abnormal diastolic function, which impairs ventricular filling and increases filling pressure, despite a normal or small ventricular cavity.
These patients have abnormal calcium kinetics and subendocardial ischemia, which are related to the profound hypertrophy and myopathic process.
How does hypertrophic cardiomyopathy usually present?
Sudden cardiac death Double carotid artery impulse, S3 gallop,
Syncope ejection systolic murmur
Presyncope
Congestive heart failure
Dizziness
Palpitations
Angina
What investigations are conducted to confirm hypertrophic cardiomyopathy?
Hemoglobin level: Anemia exacerbates chest pain and dyspnea
•Brain natriuretic peptide (BNP), troponin T levels: Elevated BNP, NT-proBNP, and troponin T levels are associated with a higher risk of cardiovascular events, heart failure, and death
•Echocardiography
•Chest Xray
•Cardiac MRI
What is the first line of treatment in the management of hypertrophic cardiomyopathy?
beta-blockers
What is restrictive cardiomyopathy?
Increased stiffness of the myocardium
Outline the abnormal physiology of restrictive cardiomyopathy
Increased stiffness of the myocardium causes ventricular pressures to rise precipitously with small increases in volume.
Thus, accentuated filling occurs in early diastole and terminates abruptly at the end of the rapid filling phase.
Patients typically have reduced compliance (increased diastolic stiffness), and the left ventricle cannot fill adequately at normal filling pressures
Reduced left ventricular filling volume leads to a reduced cardiac output.
How does restrictive cardiomyopathy usually present?
comfortable in the sitting position because of fluid in the abdomen or lungs, and they frequently have ascites and pitting edema of the lower extremities.
•The liver is usually enlarged and full of fluid, which may be painful.
•Weight loss and cardiac cachexia are not uncommon.
•Easy bruising, periorbital purpura, macroglossia, and other systemic findings, such as carpal tunnel syndrome, should be an indication for the clinician to consider amyloidosis.
•Increased jugular venous pressure is present.
•The pulse volume is decreased, consistent with decreased stroke volume and cardiac output.
What investigations are conducted to confirm restrictive cardiomyopathy?
CBC, Serology, Amylodosis check, Chest Xray ,ECG ,Echocardiography, Catheterisation, MRI/Biopsy
Outline the management pathway for restrictive cardiomyopathy
Heart failure medication
Guideline-directed medical therapy for heart failure, including angiotensin-converting enzyme inhibitors or angiotensin receptor II blockers, diuretics and aldosterone inhibitors should be initiated in patients with reduced LV
Antiarrhythmic Therapy
Immunosuppression- Steroids
Pacemaker
Cardiac transplantation
Outline the seven phases of the cardiac cycle
Atrial systole - blood ejected into ventricles, AV valve open
Isovolumetric contraction - all valves closed, ventricles contract
Rapid ejection - pressure in ventricles higher than post semi lunar valve pressure, blood ejected quickly
Slow ejection - pressure gradient falls, blood ejection slower
Isovolumetric relaxation
Rapid passive filling
Slow passive filling
Which phase of the cardiac cycle is first impaired in heart failure?
Isovolumetric relaxation
What drug should be administered as soon as possible to minimise damage to the heart in heart failure?
Beta-blockers
Cardiac stroke volume is determined by what two factors?
Energy of contraction (preload) - starlings law of the heart, cardiac contractility
Arterial pressure (afterload)
Outline Starlings law of the heart
A length-tension relationship describing how stretch of myocardium in diastole enhances contractile energy created
In Starlings law of the heart, how does a stressing myocardium cause negative effects on contractile energy?
Reduces overlap of myocardial fibres, decreased interference causes negative effect on contractile energy
What is the slower effect of Starlings law of the heart?
Sub-cellular increase in calcium stores
What is the anrep effect of Starlings law of the heart?
Increases force of contraction by increasing number of cross bridges formed
What are the two factors that determine cardiac contractility?
Sympathetic tone - sympathetic nerve fibres supplying the myocardium
Adrenaline - increasing contractile force of myocardium
What is the relationship between preload and hypovolemia?
If a patient is bleeding or dehydrated there will be less blood volume circulating so blood pressure falls and stroke volume increases this means there is less preload as there is less stretching of the myocardium to generate energy of contraction
What is afterload?
Pressure in aorta, force per unit cross section area, opposes shortening of myocardium in isotonic manner
how is afterload involved in hypertension?
Increased afterload impairs stroke volume, can get adverse effects such as negative remodelling - heart muscle thickens and pumps dysfunctionally
What is the Law of LaPlace?
Translates internal diameter radius of a chamber to wall tension and internal pressure generated by chamber. Ie internal pressure generated inside a chamber is directly proportional to wall tension
Per Law of LaPlace, internal pressure generated inside a chamber is inversely proportional to what?>
Radius of the chamber
In pathological states (e.g. heart failure / dilated cardiomyopathy), why does contractility fall (Law of LaPlace)
Radius of chamber increases meaning the chamber is unable to generate effective internal pressure
What is the equation that describes the Law of LaPlace?
P=2T/r and P=2Sw/r
P = pressure
r = radius
T = tension
Sw = wall stress x wall thickness
Increase thickness = increase pressure generated
In athletic hearts what changes can be seen to maintain BP needed?
The muscle is strengthened to increase contractile force - chamber with small radius, bigger internal force due to wall tension
Which valve closes during ventricular filling?
Mitral valve
Which valve opens during late isovolumetric contraction?
Aortic valve
Which valve closes following ejection?
Aortic valve
Which valve opens following isovolumetric relaxation ?
Mitral valve
What are the two possible types of valvular lesions?
Stenosis lesions - narrowing
Dilatation - regurgitation lesions
On which side of the heart are valvular lesions more significant and what do they lead to?
Left sided valvular lesions are more clinically significant, lead to mitral and aortic stenosis
How is aortic stenosis detected?
Heart murmuring during systole
How is mitral regurgitation detected?
Systolic murmur
why is mitral regurgitation important to treat?
Can die of heart failure, become congested so need appropriate medication - diuretics
Important to treat and replace valve when severe
How is aortic regurgitation detected?
Diastolic murmur
What are the characteristics of cardiac hypertrophy?
May have abnormal ECG, left ventricles abnormally thickened
May have abnormal thickening in wall in between chambers - can obstruct blood flow through the aorta, murmur can mimic aortic stenosis, heard in systole ‘ ejection systolic murmur;
A dilated heart leads to poor contractility, this can be caused by:
Stress induced
Infectious causes
Peripartum
Sarcoidosis
Immune disease
Ischaemic aetiology
What is arrhythmogenic right ventricular cardiomyopathy?
A group of discovers which can lead to abnormal ventricular arrhythmia - abnormal contraction, impaired cardiac output
What can infiltration of fat into the heart cause?
Abnormal diameter and function, dilated
Not pumping effectively, can also affect LV as intrinsically linked
May not be symptomatic
Can cause ventricular tachycardia and lead to sudden death (must check for family history of this)
How are valve lesions treated?
By replacing the valve before the patient becomes symptomatic or before the heart decompensates
What is cardiogenic shock?
Impairment of cardiac systolic function resulting in reduced CO
End organ dysfunction as not getting vital blood supply from stroke volume of heart
Receiving less oxygen and glucose for sufficient aerobic respiration
81% due to STEMI
What are the treatment options for cardiogenic shock?
Keep transthoracic echocardiogram at bedside to see if ventricles aren’t pumping
Early coronary angiography to visualise narrow vessels
Urgent percutaneous cornonary intervention (PCI) - stents to open up narrow arteries causing the MI, or urgent coronary artery bypass grafting
